In a What-if-World almost everything is possible. And the Fencer in this case must not have been soviet before. That's the freedom what-iffers have. It's just the Fencer "masquerading" as another plane from another country; people like Spinners and I have done it for years, just in case you didn't notice. Also re-imagining Russian aircraft to serve in NATO and traditionally western armament buying countries. Just take a deeper look into this section and the What-if Screenshot Thread.
And there is a MiG-29 for the spanish air force in the What-If Download section. And I am pretty sure, that there is also a Canadian Flanker somewhere in the Forum that had possibly been created by Spinners or somebody else.